I just iced my cake in SMBC and covered it in Satin Ice fondant. Can it sit out till 12:00 delivery tomorrow or does it need to be put in the refrigerator.

Thank you

I usually put it in the fridge overnight or for a few hours so the SMBC gets cold hard making the cake more stable for transport (although SMBC can sit out at room temperature for a few days with no problems). It takes about 2-3 hours for it to come back down to room temperature so depending on how long of a drive or when it's being served, you may want to pull it out of the fridge a little earlier.

PS - I use MMF and haven't had a problem with refrigerating it. I'm not sure about Satin Ice though.